81909342 has 48 divisors (see below), whose sum is σ = 191889360. Its totient is φ = 25163136.

The previous prime is 81909341. The next prime is 81909389. The reversal of 81909342 is 24390918.

It is a junction number, because it is equal to n+sod(n) for n = 81909297 and 81909306.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81909341) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 9418 + ... + 15890.

It is an arithmetic number, because the mean of its divisors is an integer number (3997695).

Almost surely, 2^81909342 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81909342, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (95944680).

81909342 is an abundant number, since it is smaller than the sum of its proper divisors (109980018).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81909342 is a wasteful number, since it uses less digits than its factorization.

81909342 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6537 (or 6534 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The square root of 81909342 is about 9050.3780031554. The cubic root of 81909342 is about 434.2879830317.

The spelling of 81909342 in words is "eighty-one million, nine hundred nine thousand, three hundred forty-two".